Homeland Security Secretary Jeh Johnson blasted Rep. Duncan Hunter 's suggestion that ISIS fighters have crossed the United States ' southern border into Texas .

`` Let 's not unduly create fear and anxiety in the public by passing on speculation and rumor , '' Johnson said Wednesday on CNN 's `` Situation Room . ''

Hunter , a California Republican , claimed on Fox News on Tuesday night that he 'd learned from Border Patrol officers that at least 10 ISIS fighters had been caught trying to cross the Mexican border -- and that `` you know there 's going to be dozens more that did not get caught by the Border Patrol . ''

Johnson said those claims are n't supported by `` credible , specific intelligence to that effect . '' He said public officials should `` be responsible in what we decide to share with the American public , so that the public is informed . ''

His comments came after a Homeland Security spokeswoman called Hunter 's statement `` categorically false . ''

`` I look at the intelligence reports from overseas , from our southern border , from our intelligence community virtually every day , numerous times a day , to be on the lookout for something of that nature , '' Johnson said .

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`` So what I would say to the American public is , we 're vigilant in looking out for individuals of suspicion that may be crossing our border , and we have no specific intelligence that ISIL is planning to come into the U.S. through our southern border , '' he said , using another acronym for ISIS .

Hunter spokesman Joe Kasper said the congressman stands by his comments .

`` A high level source informed the congressman -- it was also said that DHS is actively discouraging any talk of IS on the border , '' Kasper said .

`` The congressman was conveying what he knows -- and what he was told , '' he said . `` And as for DHS ' statement , it makes sense that the left hand of DHS does n't know what the right hand is doing -- it 's been that way for a long time and we do n't expect that to change . No surprise there . ''

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Homeland Security secretary says ISIS fighters have n't crossed into the U.S.

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Rep. Duncan Hunter claimed Tuesday that at least 10 had crossed the southern border

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Secretary Jeh Johnson calls those claims `` speculation and rumor ''